Fraser Horton
Fraser Horton
Last Updated on September 25, 2021

If you’re an aspiring cannabis grower who’s fascinated with how the cannabis seeds purchased from a seed bank turn into fully grown flowers with a fragrant terpene profile and cannabinoid-rich trichomes, you may also be interested in how you can merge different cannabis strains and create a new strain of your own.

Maybe you have a favorite Sativa cannabis strain and you want to mix it with a newly-discovered Indica, but are not quite sure how to effectively do it. Well, you don’t need to look any further as this article will give you all the essential information on crossbreeding cannabis, including how to do it step-by-step.

As the cannabis market continues to grow, new strains are coming to your local dispensary very often, and who knows, yours might end up there someday. After all, the most popular strains today were once the product of small yields of weed. So, to figure out how you can achieve that through crossbreeding, let’s first briefly go over the breeding process.

The 411 on Cannabis Breeding

Cannabis breeding is the process of merging two different strains to create a new strain (a hybrid or backcross), so it calls for merging a male plant and a female plant (parent strains) to combine or refine the genetics of those two plants.

For seed breeders to be able to grow healthy cannabis plants, it’s essential to have a detailed history of where the seeds came from, as well as how the genetics of both strains were combined. The main reasons why cannabis breeders combine strains is to enhance certain characteristics of one or both of the strains, increase the potency, and/or customize the aroma.

To combine the strains, the male plant needs to pollinate the female plant for it to produce seeds.

How to Breed Cannabis Plants?

The first thing a grower needs to do is select the parent strains for breeding. Next, they should move the plants to a breeding chamber to contain the pollen since a male plant can pollinate up to 20 female plants. So, to prevent cross-pollination on the plants you don’t want to be pollinated, you should separate the plants you intend to pollinate in a separate enclosed environment.

The next step would be to let the plants go through the vegetative stage which will enable them to grow and develop reproductive parts, meaning the female plants will develop pistils and calyxes, and the male plants will develop pollen sacs. 

Pollination will either happen naturally, or you’ll need to help along by getting pollen from the male plants and applying it to the female plants. When the seeds are mature enough, it’s time to harvest them and plant them.

Crossbreeding 101

Crossbreeding is an effective method for creating a new cannabis strain from two or more different parent strains that include a male plant and a female plant. While some growers aim to create a new hybrid strain in an attempt to breed the new go-to cannabis strain (for example, creating auto-flowering strains like the Ruderalis), others are creating new strains for the purpose of treating specific medical conditions. This method involves a lot of “trial and error” as not all male plants have the specific desirable traits which you’d like to pass off to the offspring. 

Now, let’s see how crossbreeding can be done in a few easy steps.

Collection of Pollen

After your male plants have developed pollen sacs, it’s time to start collecting the pollen. Take a ziplock bag, place it around the stem, and get the pollen inside the bag. You could either choose to pollinate the female plants immediately, or place the pollen in the freezer and use it within a month.

Pollinating Female Plants 

After the white pistils develop on your female plants, it’s pollination time. Separate the females you choose to pollinate in a separate room to prevent pollinating all your plants. Coat the buds with the collected pollen, cover the pollinated sites with a plastic bag, and shake once more to ensure the buds are pollinated. Remove the bag after a few hours.

Adding the Necessary Nutrients

After the pollination process, it’s time to add extra nutrients to the female plant, since “mother” plants need it. After a few weeks, you’ll start to notice the first seeds forming and bursting through the calyxes. Collect the seeds and either plant them immediately or store them in a cool, dark place (avoid freezing them).

Planting the Seeds

Before you plant the seeds, you’ll need to germinate the seeds following our guide. After your seeds have developed taproots, it’s time to plant them in your preferred growing medium and watch your marijuana plant grow.

Desirable Traits When Crossbreeding

The popular high-THC strains we know, love, and purchase at the dispensary are the result of successful crossbreeding throughout the years. However, to perfect those strains and create their own strain, cannabis growers needed to go through multiple generations of plants and try different combinations. When it comes to crossbreeding, the most important aspects for growers include:

  • The buds (look at the THC and CBD levels, the effects, the potency and smell of the plant);
  • The growing patterns (how much surface the plant will need, how much it’s expected to yield, as well as how long it’ll take for it to get to the flowering stage);
  • The durability of the strain (how resistant the plants are to pests and mold, variations in temperatures and humidity, variations in light cycles).

Other Important Factors

Creating new strains of cannabis can be a lot of fun, though you need to look into a few other aspects of breeding cannabis.

The Phenotype

One of the key aspects when breeding weed is the environment and the genetics of the plant, or in other words, the phenotype of the plant. These are the traits that the plant inherits from the parent strains, meaning, if you have two tall and lean parent plants, the new plant will also be tall and lean, however, if one is tall and the other is short, the new plant could either be short or tall.

Back-Crossing

To stabilize the phenotype of the plants, you need to try back-crossing. Back-crossing, or inbreeding, is a process that enables you to create new plants which are genetically similar to the parent by crossing a plant with the parent or a close family member. Another key step is providing the same environmental conditions for the offspring as you did with the parent strain to ensure maximum opportunity to successfully back-cross your plant.

Final Thoughts on Crossbreeding Weed

Crossbreeding may not seem all that difficult to growers, although it’s very hard to get your break and create a new strain that will take the cannabis market by storm. To make your ideal hybrid, you need to be patient, experiment a lot, and never give up, since the process of crossbreeding may take a few years before you grow a strain that fits your needs.

If you do decide to try crossbreeding, make sure you log all records during the growing period to be able to retrace your steps if you do manage to create an amazing new strain. We wish you a lot of success on your journey to create the next best hybrid strain.

Disclaimer

The information presented on this page is provided as a public service to aid in education and is derived from sources believed to be reliable. Readers are responsible for making their own assessment of the topics discussed here. In no event shall Leaf Nation be held reliable for any injury, loss or damage that could happen if using or abusing drugs.